A large scale dedicated facility such as shipyard, factory, and campus isolated from the outside world may be built along with a video surveillance system based on a high-speed wireless network such as LTE and Wi-Fi. Such a video surveillance system is characterized in requiring radio resource higher in reliability than the peer-to-peer video communication.
Thus, there is a need of building a video surveillance system allowing for use of a resource band appropriately for the characteristic of the place in the large scale facility.
IP Multimedia Subsystem (IMS) is a system for managing the resource, quality, and security of the network using Internet transfer technology such as HSPA, LTE, Wi-Fi, and wired communication network. The IMS-based radio resource management is a method applied to the 4th Generation mobile communication such as Voice over LTE (VoLTE) and specified in 3GPP TS 23.228.
FIG. 1A is a diagram illustrating the role of IMS in the conventional packet switched network. As shown in FIG. 1A, the IMS is responsible for facilitating provision of various application services to a plurality of terminals using the network such as LTE.
FIG. 1B is a block diagram illustrating a basic configuration of the IMS.
As shown in FIG. 1B, IMS is made up of various network nodes including four types of Call Session Control Functions (CSCFs) (i.e. Proxy-CSCF (P-CSCF), Serving-CSCF (S-CSCF), Interrogating-CSCF (I-CSCF), and Emergency-CSCF (E-CSCF)), Home Subscriber server (HSS), Subscription Locator Function (SLF), and Application Server (AS).
Via such nodes, the terminal exchange Session Initiation Protocol/Session Description Protocol (SIP/SDP) messages with servers or other terminals and determine communication-related conditions. At this time, the network management and resource allocation policies are determined too.